INDIANAPOLIS — As Minnesota emergency management officials brace for the “imminent collapse” of a large dam near Mankato, 13News wanted to know about the condition of our area’s largest “high-hazard” dams.
A dam classified as a high hazard means a failure could result in a loss of human life.
One of the largest high-hazard dams in central Indiana is the Eagle Creek Reservoir Dam, owned by the City of Indianapolis. According to the U.S. Army Corps of Engineers, the dam used to be rated in “poor condition.”
A Department of Public Works official told 13News, it was “conditionally poor” in 2006, but since then has been upgraded to “fair.”
Records show the City of Indianapolis has spent $11.6 million in ongoing maintenance, improvements and inspections over the last 18 years.
“The City is proactively managing that and realizes that the dam is a very important asset that we have and has a lot of potential risk associated with it,” said Shannon Killion, DPW engineering stormwater administrator. “So day in and day out, we're doing what work we can to minimize that risk as much as possible.”
State law requires dams to be inspected at least every two years by a licensed professional engineer registered in Indiana.
“The report must then be submitted to the Indiana DNR,” DNR spokeswoman Holly Lawson said. “If after an inspection, the licensed professional engineer who conducted the inspection determines that maintenance, repairs, or alterations to a high-hazard potential structure are necessary to remedy deficiencies in the structure, the owner shall perform the recommended maintenance, repairs, or alterations.”
In addition to state-mandated inspections every two years, Killion said DPW does a more detailed inspection of the Eagle Creek dam every four years.
"We'll have underwater divers go out and actually check the structure from what you can't see from just visually observing,” Killion said. “We've had people rappel off the dam (as well)."
In 2021, the City also paid for a “potential failure model analysis.”
“We brought in experts from across the country,” Killion said. “We looked at the dam and then went through and looked at ‘what is every way that this dam could potentially fail? What's the likelihood of that happening?’ to try and understand what the risk looked like and how we mitigate those risks.”
Killion told 13News that few dams are rated above “fair” in the U.S. because those are dams that were built within the last few years. Most are decades old — including Eagle Creek's, which was built in the 1960s.
“Our dam is in really good condition, given its age,” Killion said.
According to the Indiana Department of Natural Resources, the Geist Reservoir Dam, owned by Citizens Energy Group, is also rated “fair.”